I. Field
The present disclosure relates generally to communication, and more specifically to techniques for transmitting data in a wireless communication system.
II. Background
Wireless communication systems are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, etc. These wireless systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and Single-Carrier FDMA (SC-FDMA) systems.
A wireless communication system may support unicast, multicast and/or broadcast transmissions. A unicast transmission is a transmission sent to a specific terminal. A multicast transmission is a transmission sent to a group of terminals. A broadcast transmission is a transmission sent to all terminals. A unicast transmission may be sent at a rate selected to ensure reliable reception by a target terminal. Multicast and broadcast transmissions may be sent at a rate selected to ensure reliable reception by all or most recipient terminals, which may observe different channel conditions.
A conventional broadcast-multicast system, such as a MediaFLO™ system or a Broadcast and Multicast Service (BCMCS) system, is typically intended for large-scale deployment. For a large-scale broadcast-multicast system, an appropriate rate may be pre-selected through link budget studies and field testing and may be a conservative rate in order to ensure reliable reception by a high percentage of terminals in the system. The system may then use the pre-selected rate for all packets sent to the terminals. The pre-selected rate may be very conservative and may result in inefficient use of system resources in many scenarios. It may be desirable to send multicast and broadcast transmissions in an efficient manner in order to improve utilization of system resources.